I had the same problem and solved it.
(I'm using Eclipse 4.2 M6 and develop an e4 application).

I think "JNLP JREDesc in Component ignored: null" is not your problem.
The error will disappear if you remove the j2se definition(s) in your referenced jnlp file(s). However, I assume this is not your problem.

In my case, I didn't use the "osgi.bundles" property which is also missing in your start.jnlp and many tutorials.

You have to use the "osgi.bundles" property in order to "start" all your required bundles.

For instance, if you've defined
"plugins/com.ibm.icu_4.4.2.v20110823.jar" and
"plugins/org.eclipse.core.commands_3.6.0.I20110111-0800.jar"
in your referenced jnlp files, then just add the following property to your "start.jnlp" file: